2014-08-04T06:48:30ZDecoupling of ground level pressures observed in Italian volcanoes: are they driven by space weather geo-effectiveness?http://hdl.handle.net/2122/9045
Title: Decoupling of ground level pressures observed in Italian volcanoes: are they driven by space weather geo-effectiveness?
Authors: Madonia, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Romano, P.; INAF- Osservatorio Astrofisico di Catania, Italy; Inguaggiato, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia
Abstract: Investigations on correlation drops between near-ground atmospheric
pressures measured at sea level and at higher altitudes on Italian volcanoes
have been carried out. We looked for perturbations of the atmospheric
pressure field driven by volcanic activity, but not excluding possible
external triggers for the observed anomalies. Decorrelations between atmospheric
pressures measured at Stromboli Island in stations located at
different altitudes (years 2002-10) have been analysed and compared with
data from other volcanic (Vesuvius) and non volcanic (Mt. Soro) orographic
structures. We investigated as their possible triggers volcanic, meteorological
and space weather parameters, with particular attention to
Total Solar Irradiance (TSI), Kp index and Forbush decreases. Pressure
decorrelations seems to be driven by astronomic cycles, with maxima in
summer and minima in winter. A further contribution was found, seemingly
assignable to TSI anomalies, with correlation minima occurring 12
hours after these but only during phases of high Sun activity. Moreover,
during the same phases a main periodicity of about 27 days in pressure
decorrelations was revealed by FFT analysis. This period is the same of
the Sun Carrington rotation, expressing the periodic reappearance of
sunspot groups on Sun’s surface. The strong similarity between recurrences
of sunspot number and atmospheric pressure anomalies further
supports the role of the former as a possible trigger for the latter.2013-12-31T23:00:00ZMonitoraggio sismico del territorio nazionale: stato dell'arte e sviluppo delle reti di monitoraggio sismicohttp://hdl.handle.net/2122/8813
Title: Monitoraggio sismico del territorio nazionale: stato dell'arte e sviluppo delle reti di monitoraggio sismico
Authors: Sergio, Guardato; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia
Abstract: Il sistema CUMAS (Cabled Underwater Module
for Acquisition of Seismological data) è un
prodotto tecnologico-scientifico complesso nato
con il Progetto V4 [Iannaccone et al., 2008] allo
scopo di monitorare l’area vulcanica dei Campi
Flegrei (fenomeno del bradisismo).
Si tratta di un modulo sottomarino cablato e
connesso a una boa galleggiante (meda elastica). Il
sistema è in grado di acquisire e trasmettere alla
sala di monitoraggio dell’OV, in continuo e in
tempo reale, sia i segnali sismologici sia quelli di
interesse geofisico ed oceanografico (maree,
correnti marine, segnali acustici subacquei,
parametri funzionali di varia natura).
Il sistema è in grado di ricevere comandi da remoto
per variare diversi parametri di acquisizione e di
monitorare un cospicuo numero di variabili di
funzionamento.
Il sistema si avvale del supporto di una boa
galleggiante attrezzata. La boa è installata a largo
del golfo di Pozzuoli (Napoli) a circa 3 km dalla
costa. Il modulo sottomarino, collegato via cavo
alla parte fuori acqua della boa, è installato sul
fondale marino a una profondità di circa 100 metri.2010-12-31T23:00:00ZRelative ordering in the radial evolution of solar wind turbulence: the S-Theorem approachhttp://hdl.handle.net/2122/7310
Title: Relative ordering in the radial evolution of solar wind turbulence: the S-Theorem approach
Authors: Consolini, G.; INAF – Istituto di Fisica dello Spazio Interplanetario, 00133 Roma, Italy; De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia
Abstract: Over the past few decades scientists have shown growing interest in space plasma complexity and in understanding the turbulence in magnetospheric and interplanetary media. At the beginning of the 1980s, Yu. L. Klimontovich introduced a criterion, named S-Theorem, to evaluate the degree of order in far-from-equilibrium open systems, which applied to hydrodynamic turbulence showed that turbulence flows were more organized than laminar ones. Using the
same theorem we have evaluated the variation of the degree of self-organization in both Alfv´enic and non-Alfv´enic turbulent
fluctuations with the radial evolution during a long time interval characterized by a slow solar wind. This analysis seems to show that the radial evolution of turbulent fluctuations is accompanied by a decrease in the degree of order, suggesting that, in the case of slow solar wind, the turbulence
decays with radial distance.2011-12-22T23:00:00ZComplexity in the sunspot cyclehttp://hdl.handle.net/2122/5237
Title: Complexity in the sunspot cycle
Authors: Consolini, G.; INAF – Istituto di Fisica dello Spazio Interplanetario, 00133 Roma, Italy; Tozzi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia
Abstract: The occurrence of complexity in the solar cycle, as monitored by the sunspot area butterfly diagram, is investigated by means of the natural orthogonal composition (NOC) technique and information theory approach. Although the butterfly diagram may be reconstructed using only two modes as already found in other papers for the Hale cycle, on deeper investigation it is possible to notice that the high variability, complexity, and stochasticity observed during the solar cycle are missing. A full description of the complex
evolution of the solar cycle requires at least 30 modes. We show that these modes identify two different dynamical regimes, whose existence is also confirmed by the analysis of the Lyapunov exponents of the associated principal components. We suggest that the existence of these two physical dynamical regimes is at the origin of the dynamical complexity of the solar cycle. We attempt a discussion of these dynamical regimes also in terms of a nearly stable dynamo process described by the first two modes and a local superficial turbulent dynamo responsible for the more stochastic features observed in the solar cycle.2009-11-02T23:00:00ZA probabilistic approach to heterogeneity in space plasmas: the case of magnetic field intensity in solar windhttp://hdl.handle.net/2122/5031
Title: A probabilistic approach to heterogeneity in space plasmas: the case of magnetic field intensity in solar wind
Authors: Consolini, G.; INAF-Istituto di Fisica dello Spazio Interplanetario, 00133 Roma, Italy; Bavassano, B.; INAF-Istituto di Fisica dello Spazio Interplanetario, 00133 Roma, Italy; De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia
Abstract: Since the early 90s it was shown that Probability
Distribution Functions (PDFs) of small scale differences
(fluctuations) of several quantities in space plasmas display
significant departures from Gaussianity. The non-Gaussian
shape of PDFs was ascribed to intermittency and discussed
in the framework of intermittent MHD turbulence. Here, we
put the attention to the PDF of magnetic field intensity instead
of its differences showing how the PDF of such quantity
in a quiet solar wind can be related with the occurrence
of heterogeneity. In detail, we derive the shape of the PDFs
by simple statistical considerations based on the concept of
subordination in probability theory. An interpretation and a
discussion in terms of existing coherent magnetic structures
in a mechanical near-equilibrium state are also presented.2009-04-06T22:00:00ZLa variazione secolare del campo geomagneticohttp://hdl.handle.net/2122/3668
Title: La variazione secolare del campo geomagnetico
Authors: Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia1992-12-31T23:00:00ZProbable values of rise and fall off time of solar cycles 23,24, and 25http://hdl.handle.net/2122/1684
Title: Probable values of rise and fall off time of solar cycles 23,24, and 25
Authors: Ortiz de Adler, N.; Laboratorio de Ionosfera, Instituto de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman, Argentina; Elias, A. G.; Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina
Abstract: From an analysis of the rise and fall off time of solar cycles 4 to 22, a recurrence tendency of 7 cycles is observed in the rise time and, apparently, of 9 cycles in the fall off time. The envelope of these times presents a decreasing amplitude of oscillation. According to this behaviour, the rise and fall length of future solar cycles until cycle 25 can be inferred qualitatively. These values are compared with those obtained with a multiple regression method showing a good agreement.1996-04-30T22:00:00ZSolar cycle 22 control on daily geomagnetic variation at Terra Nova Bay (Antarctica)http://hdl.handle.net/2122/1494
Title: Solar cycle 22 control on daily geomagnetic variation at Terra Nova Bay (Antarctica)
Authors: Cafarella, L.; Istituto Nazionale di Geofisica, Roma, Italy; Meloni, A.; Istituto Nazionale di Geofisica, Roma, Italy; Palangio, P.; Istituto Nazionale di Geofisica, Roma, Italy
Abstract: Nine summer geomagnetic observatory data (1986-1995) from Terra Nova Bay Base, Antarctica (Lat.74.690S, Long. 164.120E, 80.040S magnetic latitude) are used to investigate the behaviour of the daily variation of the geomagnetic field at polar latitude. The instrumentation includes a proton precession magnetometer for total intensity |F| digital recordings; DI magnetometers for absolute measuring of the angular elements D and I and a three axis flux-gate system for acquiring H,D Z time variation data. We find that the magnetic time variation amplitude follows the solar cycle evolution and that the ratio between minimum solar median and maximum solar median is between 2-3 for intensive elements (H and Z) and 1.7 for declination(D). The solar cycle effect on geomagnetic daily variation elements amplitude in Antarctica, in comparison with previous studies, is then probably larger than expected. As a consequence, the electric current system that causes the daily magnetic field variation reveals a quite large solar cycle effect at Terra Nova Bay.1998-10-31T23:00:00ZThe solar-cycle variation of M(3000)F2 and its correlation with that of f0F2http://hdl.handle.net/2122/1474
Title: The solar-cycle variation of M(3000)F2 and its correlation with that of f0F2
Authors: Kouris, S. S.; Electrical Engineering Department, Aristotelian University of Thessaloniki, Greece
Abstract: Using hourly monthly-median measured values from nine long-standing ionospheric sounding stations with data sets extending over several decades, best-fit empirical relationships are established for M (3000)F2 with different solar and ionospheric indices representative of state of the solar cycle. The statistical analysis shows that there is no difference in the degree of correlation in using one index over another. Comparisons are also made with similar relationships for monthly median f0F2 determined from the corresponding measurement data sets and the degree of correlation between the two ionospheric parameters is established.1998-09-30T22:00:00ZForecast of solar maximum and minimum dates for solar cycles 23 to 29http://hdl.handle.net/2122/1435
Title: Forecast of solar maximum and minimum dates for solar cycles 23 to 29
Authors: Elias, A. G.; Laboratorio de Ionosfera, Instituto de Física, Facultad de Ciencias Exactas, Universidad Nacional de Tucumán, Argentina; Ortiz de Adler, N.; Laboratorio de Ionosfera, Instituto de Física, Facultad de Ciencias Exactas, Universidad Nacional de Tucumán, Argentina
Abstract: The solar cycle length for cycles 23 to 29 are forecasted. Two methods are analysed. In the first one, the solar cycle length is separated into its two phases í the rise time and the fall off time í and a multiple regression method is applied to each phase using lagged values as independent variables. In the second method, the multiple regression is fitted directly to the solar cycle length. The minimum and maximum solar activity dates are listed for the cycles predicted with the latter method which proves to be more accurate. Two lagged values appear in the multiple regression adjusted to the solar cycle length. One is associated with the Gleissberg period, also observed in the maximum sunspot number, and the other is coincident with one of the periodicities in the C14 time record, which is associated with solar activity variation1998-03-31T22:00:00Z